Patent DE-19613553-A1 (DE)
Title: Integrated production and fractionation of aromatic poly:amine mixtures
Inventor: KNOEFEL HELMUT DR
IPC: C07C209/60
Filed: 1996-04-04
Abstract: A process for the production of aromatic polyamine mixtures (I) with integrated fractionation and/or purification, by reacting aryl amines (II) with carbonyl compounds, especially formaldehyde (III), in presence of acid catalysts (IV) and water (at least in the last stage of the rearrangement), and optionally in series with a separate "aminal stage" to form N,N'- disubstituted condensation products in the absence of (IV) and optionally in presence of hydrophobic solvents (V). In this process, (a) the 2-phase reacted mixture (01) is (d) separated in separator C-1 into organic phase (02) and aqueous phase (03), optionally (b) after adding (II) and/or water and/or strong acid (as salts of (II) and possibly (I)), preferably in the form of a recycled aqueous phase (17), (18) and/or (19), and optionally (c) after adding hydrophobic solvent (V) which may contain (II) and/or (I); organic phase (02) is taken to counter-current extraction (C-2) against an aqueous phase containing water , acid as ammonium salts, (II) and possibly small amounts of (I), and consisting of at least parts of streams (17) and/or (18) and/or (19), in an amount such that the polyamine (I) in phase (02) is transferred quantitatively to the resulting aqueous phase (04) which is then (f) taken to extraction C-4, optionally (e) via extraction stage C-3; the polyamine-free organic phase (05) from C-2, optionally (g) after passing through extraction stage C-4 or (h) through C-4 and then C-3, is (i) recycled at suitable point(s) in the reaction sequence, but before the reaction mixture reaches separator C-1; aqueous phase (03) from C-1 is extracted in (C-4) with an organic phase (06) containing (V), generally (II) and possibly (I), which is adjusted so that the polyamine is partitioned in a controlled manner between the resulting organic (07) and aqueous phase (08) and the composition of the polyamine fraction differs as required; organic phase (07), optionally (k) via extraction C-3, or (l) after separating a part which is taken to C-2, or (m) passing through extraction C-3 and separating a part which is taken to C-2 before and/or after passing through C-3, or (n) passing through an at least  2-stage extraction C-3 comprising part-stages C-32 and C-33 and separating a part as in (m), is recycled into the reaction sequence before the end, i.e. in reactor B-1, B-3 and/or B-4, and/or passed through a washing and/or neutralisation stage to a preferably multi-stage distillation (D-3)/(D-4) and separated into a fraction (09) containing (V) and possibly (II), a fraction (10) containing (II) and possibly (V), and a residue (11) (first polyamine fraction); the aqueous phase from C-4, optionally (p) after adding water and/or (II), is (q) extracted in C-5 with an organic phase (12) containing (V), (II) and possibly small amounts of (I); the resulting polyamine-containing organic phase (13) is taken via wash/neutralisation stage (E-2) and distilled in stage (E) to give distillate fraction(s) (14) containing (V) and (II) and a residue (16) (second polyamine fraction); the polyamine-free aqueous phase (17) from C-5), optionally (r) after removing water in evaporator (C-7) to form stream (18) or (s) extracting amine in stage C-6 to increase the degree of protonation, is re-used, by returning (17), and/or (18) and/or (19) (if present), partly to the reaction sequence as a catalyst solution and partly to extraction stage C-2, any remaining residue being added to the reaction mixture as in (b) and/or taken to stage C-3.